Entities, no matter what operating system they have, private, public, banking, have as a purpose the value adding. The internal audit has its contribution to the achievement of this goal. This research explains the tridimensional approach of the concept of internal audit and identifies the elements that emphasize, in a tridimensional way, the internal audit. The steps of the reaserch take into consideration a synthesis of the materials published by the national and international accounting standards, by professional bodies, papers on this theme proposed for debat, as well as materials of the economic entities